Alberto Goffi1, Niall D Ferguson. 1. aInterdepartmental Division of Critical Care Medicine bUniversity Health Network cDepartment of Medicine dDepartment of Physiology, University of Toronto eMount Sinai Hospital, Toronto, Ontario, Canada.
Abstract
PURPOSE OF REVIEW: High-frequency oscillatory ventilation (HFOV) has been considered a potentially ideal mode of lung-protective ventilation. A recent meta-analysis suggested improved oxygenation and reduced mortality in adults and children with acute respiratory distress syndrome (ARDS), but the use of outdated control strategies and small numbers of patients in many of the studies rendered these findings hypothesis-generating only. RECENT FINDINGS: During 2013, two large randomized controlled trials comparing HFOV with a conventional lung-protective ventilation were published - the Oscillation for Acute Respiratory Distress Syndrome Treated Early (OSCILLATE) and the Oscillation in ARDS (OSCAR) trials. These trials suggested no benefit or even harm with HFOV in adults with early moderate-to-severe ARDS. In this article, the major characteristics of these two studies and the possible reasons for failure to achieve the expected theoretical benefits are reviewed. Moreover, future directions with potential new technical advances and the use of new bedside monitoring techniques are addressed. SUMMARY: The OSCILLATE and OSCAR trials showed that the early application of HFOV in moderate-to-severe adult ARDS does not reduce mortality compared with conventional ventilation strategies. Future studies on HFOV will need to identify those patients who might benefit most from HFOV and to determine the best oscillator settings. Both goals require an improved capability of monitoring recruitment and overdistension, and oscillatory volumes.
PURPOSE OF REVIEW: High-frequency oscillatory ventilation (HFOV) has been considered a potentially ideal mode of lung-protective ventilation. A recent meta-analysis suggested improved oxygenation and reduced mortality in adults and children with acute respiratory distress syndrome (ARDS), but the use of outdated control strategies and small numbers of patients in many of the studies rendered these findings hypothesis-generating only. RECENT FINDINGS: During 2013, two large randomized controlled trials comparing HFOV with a conventional lung-protective ventilation were published - the Oscillation for Acute Respiratory Distress Syndrome Treated Early (OSCILLATE) and the Oscillation in ARDS (OSCAR) trials. These trials suggested no benefit or even harm with HFOV in adults with early moderate-to-severe ARDS. In this article, the major characteristics of these two studies and the possible reasons for failure to achieve the expected theoretical benefits are reviewed. Moreover, future directions with potential new technical advances and the use of new bedside monitoring techniques are addressed. SUMMARY: The OSCILLATE and OSCAR trials showed that the early application of HFOV in moderate-to-severe adult ARDS does not reduce mortality compared with conventional ventilation strategies. Future studies on HFOV will need to identify those patients who might benefit most from HFOV and to determine the best oscillator settings. Both goals require an improved capability of monitoring recruitment and overdistension, and oscillatory volumes.